Unable to switch from to rapid to ahci sdd controller to install linux

I know this might be a super obvious question, but my friend has windows installed on a dell Inspiron 5501. He has been wanting to switch to Linux for a long time and finally decided to make the change yesterday, but we encountered lots of issues first which was BitLocker which we removed, next we have been stuck on raid mode as monjaro won’t recognise his internal SSD unless I ran a few commands and figured out that the problem is with the drive being in rapid mode only but each time I change it into ahci it gets changed back to rapid. I have tried all the top hits on google switched to safe mode and then did too still it gets changed back to raid, we decided to take his SSD and add it to another laptop and then we formatted the SSD and installed monjaro on it using that laptop it installed properly and was running smooth, but as we switched back the SSD to his laptop it gets stuck on the monjaro loading screen and doesn’t load, would be really helpful if someone could help. We are stuck on this for 48 hours now. We really want to install monjaro and get rid of windows proprietary stuff

The change has to be done in BIOS settings. If the BIOS is not saving your settings, then better look for a BIOS update and/or contact Dell to troubleshoot that.